Rapid Screening of Traditional Rice Cultivars against Drought Using Tolerance Indices of Seedlings

Aim: To screen the traditional cultivars of rice based on the tolerance indices of seedling characteristics. Study Design: The experimental plan used was Complete Randomized Design with 59 treatments (genotypes) and two replications. Place of Study: P.G. Laboratory, Department of Seed Science and Technology, Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar district, West Bengal, India. Methodology: Seedling was raised in glass in two sets- PEG-mediated drought and normal conditions. Results: All the seedling characters showed highly significant differences among the varieties, different culture conditions as well as interaction between varieties and environment. Most of the cultivars exhibited reduction in number of primary roots per plant, root length, root fresh weight, root dry weight, shoot length, shoot fresh weight and shoot dry weight. Finally the cultivars were grouped under three categories- tolerant, semi-tolerant and susceptible based on mean tolerance index (MTI). The cultivars having ≥ 90.00, MTI Kashiya binni, Jhagri kartik and Garu Chakua were considered as tolerant. Among those three cultivars, Kashiya binni was found to be highly tolerant to drought as its MTI was ≥ 100.00 (114.96). Subsequently 22 cultivars were classified as semi-tolerant. In conclusion, the tolerance indices of seedling traits and subsequently the MTI can be used for rapid screening of rice genotypes for water stress.